Action Points* Life expectancy for patients with Parkinson's disease is poorer than some previous studies have suggested, with barely one-third of patients surviving six years with the condition.* The incidence of dementia was common and markedly increased the risk of death in Parkinson's disease, whereas women, Hispanics, and individuals of Asian ancestry were at lower risk of death.* Life expectancy for patients with Parkinson's disease is poorer than some previous studies have suggested, with barely one-third of patients surviving six years with the condition, researchers said.

Among nearly 140,000 Medicare beneficiaries with Parkinson's disease diagnosed in 2002 -- about half of whom were younger than 80 -- 64% had died by 2008, reported Allison W. Willis, MD, and colleagues at Washington University in St. Louis.

This rate was similar to that seen in Medicare patients suffering myocardial infarctions and Alzheimer's disease, and substantially higher than in those diagnosed with congestive heart failure, chronic obstructive pulmonary disease (COPD), or colorectal cancer, the researchers pointed out in Archives of Neurology.

Willis and colleagues also found that the incidence of dementia was common and markedly increased the risk of death in Parkinson's disease, whereas women, Hispanics, and individuals of Asian ancestry were at lower risk of death during the study period.

Geography didn't appear to affect mortality in Parkinson's disease patients with one exception -- those living in urban areas known to have high levels of industrial manganese pollution were at almost 20% higher risk of death than those in low-pollution areas (hazard ratio 1.19, 95% CI 1.10 to 1.29 for areas in the top versus bottom quartile of manganese pollution).

On the other hand, there was no difference in death rates between areas of high and low lead pollution, the researchers indicated.

Willis and colleagues argued that these findings on metals pollution "calls into question whether continued exposure to basal ganglia toxins after symptom onset may accelerate the clinical course of idiopathic Parkinson's disease or be associated with the development of important comorbidities."

In their study, the researchers looked at Medicare records for all patients with claims related to Parkinson's disease in 2002, who lacked such claims in the previous two years. The claims were examined through 2008.

Some 70% of the patients included in the analysis had dementia during the six-year follow-up period, although the records indicated that almost half had clinical evidence of dementia or cognitive impairment before receiving the Parkinson's disease diagnosis.

Among patients with dementia, the hazard ratio for death during the study was 1.72 (95% CI 1.69 to 1.75) after adjusting for age, sex, race, initial dementia status, comorbidities, and socioeconomic deprivation score.

But dementia was not seen equally often among the sexes or ethnic groups, and these patterns were different for mortality.

"The highest frequency of dementia was found in African-American individuals (78.2%) followed by Hispanic individuals (73.1%)," Willis and colleagues wrote, whereas rates among whites and Asians were lower at 69% and 66.8%, respectively.

Blacks also had the highest mortality rates at 66.4%, but whites were a close second at 64.6%. Hispanics and Asians, on the other hand, died at rates of 55.4% and 50.8%, respectively.

Not surprisingly, risk of both death and dementia rose substantially with patients' age.

But the overall six-year mortality rate of 64.4% in Parkinson's disease stood in contrast to rates calculated for the Medicare population on the same basis for conditions more commonly recognized as life-threatening, Willis and colleagues noted. These included:

At the same time, the claims data showed that, among some 13,000 Parkinson's disease patients who died in 2006, most received a great deal of healthcare during their terminal year.

Three-quarters were hospitalized at least once and the average number of hospitalizations was 3.4. Infections and cardiovascular disease were the most common reasons cited for these admissions. In only 1% of hospitalizations was Parkinson's disease included among the 10 primary illnesses recorded in patients' charts.

Willis and colleagues suggested that, because most Parkinson's disease patients are not treated by neurologists, the doctors they do see may spend most of the visits managing the Parkinson symptoms and not enough on patients' other conditions.

Moreover, some symptoms of cardiovascular disease, infections, and other disorders, such as fatigue and weakness, may mistakenly be attributed to Parkinson's disease.

They also asserted that their finding of an association between manganese pollution and mortality risk is another in a line of studies implicating environmental toxins in Parkinson-related neurodegeneration.

The same group had previously reported that Parkinson's disease incidence was highest in counties with high versus low levels of industrial manganese pollution (Am J Epidemiol 2010; 172: 1357-1363.)

Willis and colleagues also cited another study finding that Parkinson risk was increased in areas exposed to a manganese-containing herbicide called maneb (Am J Epidemiol 2009; 169: 919-926).

Limitations to the study include possible errors and omissions in Medicare data as well as the possibility of different healthcare-seeking behaviors in various populations and other unmeasured confounders.

The researchers also lacked data on lifetime exposures to manganese and other pollutants, relying instead on recent pollution levels in beneficiaries' current residences.

The study was funded from several National Institutes of Health grants and by the St. Louis Chapter of the American Parkinson Disease Association, the American Parkinson Disease Association, Walter and Connie Donius, and the Robert Renschen Fund.

Study authors declared they had no relevant financial interests.

Mon Jan 30, 2012 12:38 am

mockturtle

Joined: Wed Dec 30, 2009 1:46 pmPosts: 3213Location: WA

Re: 64% of those with PD dead within 6 years of DX

Wow, that certainly flies in the face of most existing prognoses. It would be interesting to find out if any of those studied had LBD. Sounds like some of them did. Or even if it made any difference.

_________________Pat [68] married to Derek [84] for 38 years; husband dx PDD/LBD 2005, probably began 2002 or earlier; late stage and in a SNF as of January 2011. Hospitalized 11/2/2013 and discharged to home Hospice. Passed away at home on 11/9/2013.

Mon Jan 30, 2012 2:22 am

cdw

Joined: Fri Nov 05, 2010 11:30 pmPosts: 318Location: southern cali

Re: 64% of those with PD dead within 6 years of DX

wow... had no idea... thought it had a much longer life span... i agree it would be interesting to hear how the folks with lbd played into the mix.. or not..

Presumably since the diagnosing MDs were not specialists, there's a mix in here of all four atypicals -- DLB, PSP, CBD, and MSA -- which are all faster-progressing.

Mon Jan 30, 2012 1:29 pm

labeckett

Joined: Thu Apr 21, 2011 9:07 pmPosts: 248

Re: 64% of those with PD dead within 6 years of DX

Hi Robin,Thanks, as always, for this posting!

The finding does not seem surprising. David Bennett and some other colleagues and I published a short paper in the Lancet about 15 years ago, based on a population-based prospective cohort study in East Boston with careful, uniform ascertainment of neurologic problems, that demonstrated a 2-fold increase in risk of death in people with Alzheimer's disease who had "parkinsonism" (parkinsonian symptoms in 2 or more of the 4 classic domains of rigidity, bradykinesia, tremor and gait problems). So this was not even a diagnosis of PD, just parkinsonism, which was associated with a worse prognosis even after taking into account age, sex, and other predictors of increased likelihood of death. (Lancet 1996. vol 351, p 1631.)

There are lots of possible explanations, both for the increased mortality and the impact of specialty care (including, as they say, differential diagnosis rates for milder cases). It's pretty clear that damage in the brain regions associated with movement disorders, with or without dementia, is an ominous sign.

It would also be interesting to know how many died as a result of being given bad drugs.

_________________Pat [68] married to Derek [84] for 38 years; husband dx PDD/LBD 2005, probably began 2002 or earlier; late stage and in a SNF as of January 2011. Hospitalized 11/2/2013 and discharged to home Hospice. Passed away at home on 11/9/2013.

This is surprising to me. Not the part that those with dementia and parkinsonism die quickly. (Though I've heard the opposite of what you said -- I've heard that those with PD plus dementia symptoms die sooner than those with PD and no dementia symptoms. So the dementia is the life-limiting symptom, not the parkinsonism.)

But the part about such a large percentage having shorter-than-expected survival time. I'd always been told that life expectancy with PD is about the same as without PD -- but the last several years of your life may be low-quality ones. I guess there should be one big caveat to that -- only if you don't have dementia. Studies vary on the percentage of those with PD who will get dementia (40% - 70%).

The other surprising part was about the idea there was no difference in low-lead or high-lead pollution areas.

Robin

Mon Feb 06, 2012 8:40 pm

labeckett

Joined: Thu Apr 21, 2011 9:07 pmPosts: 248

Re: 64% of those with PD dead within 6 years of DX

Hi Robin,

I think the challenge is having a valid study design - uniform ascertainment of diagnosis, prospective cohort, suitable comparison group. That's the real advantage of a population-based study like East Boston or the Chicago Healthy Aging Project or other similar studies. It's my impression that in most such studies that people with parkinson's or parkinsonism are at higher risk of death than people of comparable age without those symptoms, whether you look within the group with dementia or within a dementia-free subgroup. But of course there is considerable variation from person to person.

The lead exposure part is interesting, also, but I'd think it would be hard to know lifelong exposure because we have such a mobile population. If you can only go by residence at time of death, you probably have a lot of non-differential misclassification of early life exposure, that is, some people who grew up heavily exposed will have moved and look unexposed, and vice versa. This problem of measuring exposure makes it generally harder to detect an effect.

You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum